Hojotai Mozukus

A man named Shiyouji Shunpei is in a hotel room when three small creatures appear through the wall. They seek a human to form a contract with and randomly choose him. Without much choice, Shiyouji agrees and becomes bound to the creatures. His new task involves fighting other beings that pose a threat to humans. He encounters a woman who works in this field and encourages him to leave his regular job to fully commit to his new role. Shiyouji is not particularly impressive, but he must now take on the challenge of being a hero.